VMware Paravirtual SCSI adapter: Is it really that much faster?

I asked the same question myself after reading a best practice guide from Datrium that suggested using the VMware PVSCSI controller instead of the default recommendation of the LSI SAS controller that VMware makes when you create a Windows VM.

Out of curiosity I spun up a new server 2016 VM. 4 Cores 8GB of RAM, and a 100GB drive, hosted on my Datrium storage to find out how much of a difference there was.

For this test I ran during a normal production workload, and used Microsoft DiskSpd with a 16k IO size (my current average for my app servers) to test to see what we would get for results. The specific command I used was

So overall we see roughly a 4% performance increase across the board. Not groundbreaking numbers, however if you’re trying to squeeze every last drop of performance out of your VMs this could be a big step in the right direction.

Speaking of squeezing every last drop, lets see what happens when we test against a ReFS formatted disk.